//回调
function demo(callback)
{
    callback(1)
}
demo(function(e) 
{
    console.log(e)
})

//取值
function demo(callback)
{
    var opts = 
    {
        ids: [1,2,3,4],
        list: ['hello','ajax','callback','world']
    }
    callback(opts)
}
demo(function(e) 
{
    console.log(e)
})